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At least 487 records · Page 27

Design and evaluation of experimental ceramic automobile thermal reactors

The paper summarizes the results obtained in an exploratory evaluation of ceramics for automobile thermal reactors. Candidate ceramic materials were evaluated in several reactor designs using both engine dynamometer and vehicle road tests. Silicon carbide contained in a corrugated metal support structure exhibited the best performance, lasting 1100 hours in engine dynamometer tests and for more than 38,600 kilimeters (24,000 miles) in vehicle road tests. Although reactors containing glass-ceramic components did not perform as well as silicon carbide, the glass-ceramics still offer good potential for reactor use with improved reactor designs.

Stone, P. L.↗

Cryogenic storage tank thermal analysis

Parametric study discusses relationship between cryogenic boil-off and factors such as tank size, insulation thickness and performance, structural-support heat leaks and use of vapor-cooled shields. Data presented as series of nomographs and curves.

Wright, J. P.↗

Solar concentrator/absorber

Collector/energy converter, consisting of dual-slope optical concentrator and counterflow thermal energy absorber, is attached to multiaxis support structure. Efficient over wide range of illumination levels, device may be used to generate high temperature steam, serve as solar powered dryer, or power absorption cycle cooler.

Von Tiesenhausen, G. F.↗

Mount mechanisms for the Saturn 5/Apollo mobile launcher at John F. Kennedy Space Center

A support system was designed to resist hurricane wind loads at the launch pad and to allow the supported structural frame to expand and contract freely under wide ranges of temperature. This system consists of six mount mechanisms devised to meet the previously stated requirements plus a load-carrying capacity for each of 3.2-million kilograms (7-million pounds) downward and 1.6-million kilograms (3.5-million pounds) upward. A similar but lighter system of six mount mechanisms was designed for use in the sheltered environment of the vehicle assembly building. Each requirement and design result is discussed, and each mount mechanism is defined by location and type with references to visual presentations.

Balke, H. A.↗

Carbon distribution profiles in lunar fines

Radial distribution profiles of elemental carbon in lunar soils consisting of particles in the size range of 50 to 150 microns were investigated. Initial experiments on specimen preparation and the analysis of prepared specimens by Auger electron spectrometry (AES) and scanning electron microscopy (SEM) are described. Results from splits of samples 61501,84 and 64421,11, which were mounted various ways in several specimen holders, are presented. A low carbon content was observed in AES spectra from soil particles that were subjected to sputter-ion cleaning with 960eV argon ions for periods of time up to a total exposure for one hour. This ion charge was sufficient to remove approximately 70 nm of material from the surface. All of the physically adsorbed carbon (as well as water vapor, etc.) would normally be removed in the first few minutes, leaving only carbon in the specimen, and metal support structure, to be detected thereafter.

Hart, R. K.↗

Thermal performance of an integrated thermal protection system for long-term storage of cryogenic propellants in space

It was demonstrated that cryogenic propellants can be stored unvented in space long enough to accomplish a Saturn orbiter mission after 1,200-day coast. The thermal design of a hydrogen-fluorine rocket stage was carried out, and the hydrogen tank, its support structure, and thermal protection system were tested in a vacuum chamber. Heat transfer rates of approximately 23 W were measured in tests to simulate the near-Earth portion of the mission. Tests to simulate the majority of the time the vehicle would be in deep space and sun-oriented resulted in a heat transfer rate of 0.11 W.

Dewitt, R. L.↗

Study of noise and inflow distortion sources in the NASA QF-1B fan using measured blade and vane pressures

Pressure transducers were installed on the blades and vanes of QF-1B, a transonic-tip-speed fan from the NASA Quiet Fan Program which was tested on the outdoor quiet fan test facility at NASA-Lewis. Signals from the transducers and from far field microphones were analyzed to determine sources of nonuniform inflow and noise. The nonuniform inflow was mostly unsteady with roughly equal contributions from atmospheric turbulence and rig interference. The rig interference was largest at the bottom and appeared to be generated by the support structure which was located behind the inlet lip under the fan. Interaction of this inflow distortion was the dominant source of noise at 1, 2, and 3 times blade passing frequency (BPF) at 60, 70, and 80 percent of design speed. At 90 percent speed, noise at BPF was dominated by the steady rotor field. A broadband spectrum peak centered at about 2.2 times BPF was identified as rotor/stator interaction stemming from a high frequency rotor exit flow component. The remaining broadband energy from 0.3 to 3.5 times BPF was attributed to the better known type of rotor/stator interaction associated with rotor wake turbulence.

Hanson, D. B.↗

Diffraction grating transmission efficiencies for XUV and soft X rays

The manufacture and properties of a grating intended for extrasolar X-ray studies are described. The manufacturing process uses a split laser beam exposing an interference pattern on the photoresist-coated glass plated with a nickel parting layer. The grating, supporting structure, and mounting frame are electrodeposited on the nickel parting layer, and the final product is lifted from the glass substrate by selective etching of the nickel. A model was derived which relates the number of counts received in a given order m as a function of photon wavenumber. A 4-deg beam line was used to measure the efficiencies of gold transmission gratings for diffraction of X-rays in the range of 45 to 275 eV. The experimental results are in good agreement with model calculations.

Schnopper, H. W.↗

Silicon solar photovoltaic power stations

Modular design of components and arrays, cost estimates for modules and support structures, and cost/performance analysis of a central solar photovoltaic power plant are discussed. Costs of collector/reflector arrays are judged the dominant element in the total capital investment. High-concentration solar tracking arrays are recommended as the most economic means for producing solar photovoltaic energy when solar cells costs are high ($500 per kW generated). Capital costs for power conditioning subsystem components are itemized and system busbar energy costs are discussed at length.

Chowaniec, C. R.↗

Experimental data and theoretical analysis of an operating 100 kW wind turbine

Part of the cooperative effort between NASA and ERDA has been the design and the erection of an experimental wind turbine by the NASA-Lewis Research Center. This 100 kW turbine, designated the Mod-O, is located at the NASA Plum Brook site near Sandusky, Ohio. Experimental test data have been correlated with analyses of turbine loads and complete system behavior of the 100 kW Mod-O wind turbine generator over a broad range of steady state conditions, as well as during transient conditions. The deficit in the ambient wind field due to the upwind tower turbine support structure was found to be very significant in exciting higher harmonic loads associated with the flapping response of the blade in bending.

Linscott, B. S.↗

Vibration-free thermal link

System designed to hold laser at temperature of cold tip of helium refrigerator uses thermally-conducting flexible straps and special layered support structure.

Jennings, D. E.↗

Fastener for thermal insulation blankets

Serrated-stem fastener, similar to those that hold wire harnesses, has been adapted to attach blankets to supporting structures. Easy installation and removal implemented.

Cole, J. D.↗

Design study of the deepsky ultraviolet survey telescope

Preliminary mechanical design and specifications are presented for a wide field ultraviolet telescope and detector to be carried as a Spacelab payload. Topics discussed include support structure stiffness (torsional and bending), mirror assembly, thermal control, optical alignment, attachment to the instrument pointing pallet, control and display, power requirements, acceptance and qualification test plans, cost analysis and scheduling. Drawings are included.

Page, N. A.↗

Two-dimensional oscillating airfoil test apparatus

A two-dimensional oscillating airfoil test apparatus is presented as a method of measuring unsteady aerodynamic forces on an airfoil or rotor blade section. The oscillating airfoil test rig, which was built for use in NASA Ames Research Center's 11x11-foot Transonic Wind Tunnel (speed range M = 0.4 - 1.4), allows determination of unsteady loadings and detailed pressure distributions on representative airfoil sections undergoing simulated pitching and flapping motions. The design details of the motion generating system and supporting structure are presented.

Gibson, F. L.↗

Experimental data and theoretical analysis of an operating 100 kW wind turbine

Experimental test data are correlated with analyses of turbine loads and complete system behavior of the ERDA-NASA 100 kW Mod-0 wind turbine generator over a broad range of steady state conditions, as well as during transient conditions. The deficit in the ambient wind field due to the upwind tower turbine support structure is found to be very significant in exciting higher harmonic loads associated with the flapping response of the blade in bending.

Linscott, B. S.↗

Development and testing of shingle-type solar cell molecules

The details of a shingle module design which produces in excess of 97 watts/sq m of module area at 1 kW/sq m insolation and at 60 C are reported. This selected design employs a tempered glass coverplate to provide the primary solar cell structural support. The fabrication and testing of a preproduction module of this design has demonstrated that this selected approach will meet the environmental testing requirements imposed by the contract.

Shepard, N. F.↗

Nodding feed antenna for communications with satellites in synchronous orbit

The design, fabrication, and performance of a parabolic, ground receiving antenna system with a feed that nods in one axis producing a maximum beam deviation 1.1 deg from boresight is described. The antenna design was: (1)to lower the weight (and the subsequent cost) of the supporting structure and the actuator motors for a tracking antenna by moving just the feed; (2) to use a manual tracking system eliminating the need for expensive electronic controls or computers; (3) to provide for several hours of unattended operation; and (4)to permit operation of the antenna by unskilled personnel. Also described are some physical and orbital phenomenon that effect the operation or design of the antenna. One is the motion of a nearly geostationary satellite due to gravitational forces from the sun, the moon, and other stellar bodies. Others are the rotation of the nodding axis and the feed polarization as a function of the location of the station on the earth. A comparison of per unit cost was made for one unit and a quantity of 100.

Smetana, J.↗

Typical uses of NASTRAN in a petrochemical industry

NASTRAN was principally used to perform failure analysis and redesign process equipment. It was also employed in the evaluation of vendor designs and proposed design modifications to existing process equipment. Stress analysis of forced draft fans, distillation trays, metal stacks, jacketed pipes, heat exchangers, large centrifugal fans, and agitator support structures are described.

Winter, J. R.↗